AVS 50th International Symposium
    Semiconductors Wednesday Sessions
       Session SC+EM-WeP

Paper SC+EM-WeP5
Linear Magnetoresistance in LaSb@sub 2@: The Role of Charge-Density Waves@footnote *@

Wednesday, November 5, 2003, 11:00 am, Room Hall A-C

Session: Poster Session
Presenter: R.L. Kurtz, Louisiana State University
Authors: A. Acatrinei, Louisiana State University
J.W. Richardson, Argonne National Laboratory
D. Young, Louisiana State University
D. Browne, Louisiana State University
Y. Losovyj, Louisiana State University
P.T. Sprunger, Louisiana State University
R.L. Kurtz, Louisiana State University
Correspondent: Click to Email
LaSb@sub 2@ exhibits a giant linear magnetoresistance@footnote 1@ to very high fields (40T) yet it is composed of non-magnetic elements. This work reports on the role of charge-density waves (CDW) in providing a magnetic response within the two-dimensional constraints of this layered compound. Single-crystals of LaSb@sub 2@ were grown in an excess Sb flux using high-purity La and Sb and X-ray diffraction measurements confirm that it has an orthorhombic crystal-structure with a=6.38 b=6.23 and c=18.75Å. The layered structure of Sb planes separated by bi-layers of La-Sb chains gives the material a micacious appearance. X-ray measurements suggest a mosaic spread of ~0.5-1° and it is likely that the material is highly twinned. When the material is cleaved in uhv, STM studies give flat terraces mostly separated by the unit cell height and, occasionally, we observe half-unit cell steps. Neutron diffraction measurements show temperature-dependent peaks that are not from the orthorhombic structure but have been attributed to the CDWs. Further clues to the potential origin of charge-density waves come from a comparison of photoemission and density-functional studies. Photoemission studies show that the electronic structure is highly two-dimensional. Density functional theory predicts nearly square tube-like Fermi surfaces that extend along the c direction and provide the opportunity for a high degree of nesting within the basal plane. It is this nesting that provides an electronic mechanism to couple charge density oscillations to the electronic structure. A high-resolution study of the CDW gap opening at FS will be presented and discussed in terms of the role of CDWs in the magnetic response. @FootnoteText@@footnote *@We would like to acknowledge Argonne's IPNS, the LSU CAMD synchrotron light source, and the NSF for their support of this work. @footnote 1@ Bud'ko, Canfield, Mielke, et al., Phys. Rev. B 57, 13624 (1998).